The invention relates to a method of attaching a cover sheet by adhesive bonding to the spine of a book block formed of bound printed sheets in the production of books, brochures, and similar products.
In a known method of this type, after the binding process, book blocks, which are following one another on a transport path at regular distances, are respectively fed the inner side of the cover sheet which is oriented for adhesive bonding, facing the spine of the book block. The inner side of the cover sheet is subsequently pressed to the spine of the book block as well as to the lateral flanks of the spine of the book block.
During perfect binding, the printed sheets which were gathered to form book blocks, provided with or without endpaper, are supplied to a circulating transport apparatus of a perfect binder having spaced collet chucks. In the clamped or pressed-together state, the book blocks then normally pass through various processing stations in which they are milled, notched, cleaned and glued at the spine. The attachment of endpapers may also take place once the completed book blocks are available. An equivalent state can also be accomplished with printed sheets that were thread-stitched to form book blocks.
The bound book blocks then pass through a cover feeder station where a cover that is made to fit the spine is supplied to the book block. In a known principle, the planar covers are made available during this process while standing upright in a magazine and they are pulled out of the magazine individually in an upward direction. Oriented horizontally, the covers reach the casing-in station from underneath via a groove unit. In the casing-in station, the book block provided with adhesive on its spine and laterally of the spine is bound by way of the adhesive to the inner side of the cover. Afterwards, the side portions of the cover are placed in a lateral upward position and are pressed to the narrow spine flanks in the pressing station which follows. For the reliable bonding of the covers to the cased-in book blocks, a special, effective pressing is required. To this end, a pressing pressure must be applied on both sides, and, at the same time, the spine portion of the cover must be pressed against the spine of the book block, this being disclosed in, for example, "Perfect Binding Technology" ["Technologie der Klebebindung"]by Alfred Furler, 1971.
Only after a subsequent drying step are the roughs of the books trimmed along the edges.
These known feeder stations are constructed in a complex manner and they are not suitable for higher throughput rates.